83 lines
2.2 KiB
Factor
83 lines
2.2 KiB
Factor
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! Copyright (C) 2020 .
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! See http://factorcode.org/license.txt for BSD license.
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USING: alien.syntax math io.encodings.binary kernel io io.files locals endian bit-arrays ;
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USING: prettyprint ;
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USING: flac.metadata.private flac.metadata ;
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QUALIFIED: bitstreams
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IN: flac.decoder
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ALIAS: read-bit bitstreams:read
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CONSTANT: sync-code 16382
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ERROR: sync-code-error ;
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ENUM: flac-channel-assignment
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channel-assignment-independent
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channel-assignment-left-side
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channel-assignment-right-side
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channel-assignment-mid-side ;
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ENUM: flac-frame-number-type
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frame-number-type-frame
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frame-number-type-sample ;
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ENUM: flac-subframe-type
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subframe-type-constant
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subframe-type-verbatim
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subframe-type-fixed
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subframe-type-lpc ;
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ENUM: flac-entropy-coding-method
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entropy-coding-partioned-rice
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entropy-coding-partioned-rice2 ;
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TUPLE: subframe
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{ type maybe{ subframe-type-constant
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subframe-type-verbatim
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subframe-type-fixed
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subframe-type-lpc } } ;
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TUPLE: frame-header
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{ blocksize integer }
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{ sample-rate integer }
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{ channels integer }
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{ channel-assignment maybe{ channel-assignment-independent
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channel-assignment-left-side
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channel-assignment-right-side
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channel-assignment-mid-side } }
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{ bits-per-sample integer }
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{ number-type maybe{ frame-number-type-frame frame-number-type-sample } }
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{ number integer }
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{ crc integer } ;
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TUPLE: frame-footer
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{ crc integer } ;
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:: read-sync-code ( bitstream -- ? )
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14 bitstream read-bit sync-code = ;
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:: (decode-frame-header) ( bitstream -- )
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[
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bitstream read-sync-code [ sync-code-error ] unless
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1 bitstream read-bit drop
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1 bitstream read-bit drop
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4 bitstream read-bit integer>bit-array .
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4 bitstream read-bit integer>bit-array .
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] with-big-endian ;
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: decode-frame-header ( -- )
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[
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3 read bitstreams:<msb0-bit-reader> (decode-frame-header)
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] with-big-endian ;
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: decode-file ( filename -- )
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binary
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[
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read-flac-magic [ not-a-flac-file ] unless
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read-stream-info drop
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skip-metadata
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decode-frame-header
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] with-file-reader ;
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